Radiocabinet



Aug. 1, 1933. c. BOL 1,920,741

RADIOCABINET Filed Sept. 11, 1928 INVENTOR CORNELIS 501.

-4a /Mwww A ORNEY Patented Aug. 1, 1933 UNITED STATES 1,920,741 RADIOOABINET Cornelis Bol, Eindhoven, Netherlands, assignor to Radio Corporation of America, a Corporation of Delaware Application September 11, 1928, Serial No. 305,286, and in the Netherlands September 20,

2 Claims. (01. 250-16) This invention has reference to a receiving set for radio telephony, telegraphy, or the like. These devices contain tuning elements, such as variable condensers, which serve to syntonize definite oscillation circuits consisting of a self-inductance L and a capacity C. It has been found that these oscillation circuits are extremely sensitive and that low capacitive influences may have an interfering effect. It is known, in order to prevent these influences, to surround the tuning elements by a screening metal envelope.

The electrical devices are usually enclosed in a' case which is constructed of wood, ebonite, bakelite, or similar material. If the device is surrounded by such a case it is necessary to construct a separate metal envelope for the tuning elements and to arrange it in the case.

According to the invention the cabinet comprises a case of which the walls or portions of the walls consist of insulating material which is coated with a metal layer, which metal is sprayed on in a state of pulverization. If the inner side of the wall is coatedwith the metal layer the wall can be prolonged'by metal partitions or walls. As mentioned before, the invention is particularly advantageous in connection with devicesin which tuning means are arranged.

The invention will be more clearly understood by reference to the accompanying drawing. In the drawing:

Figure 1 is a perspective view of a case of a receiving set for radiotelephony.

Figure 2 is a perspective view of the case, part of the wall being broken away.

Figure 3 is a side wall of the case which consists of insulating material and is partly coated with a metal layer.

In Figure 2 the inner part of the device is shown. It is separated into two parts by a horizontal wall a. In the upper part tuning elements such, for example, as variable condensers, are to be arranged. It is desirable that these elements be surrounded by a metal envelope. The

partition a may be made of metal, and the walls 12, c, and (2 made of ebonite, bakelite, or wood,

provided on the inner side with a metal layer.

This layer may be formed on'the walls by spray-.-v

erators, and other electrical devices where shield-- ing is desirable.

What I claim is: I

1. A method of constructing radio cabinets which comprises partitioning the cabinet interior into at least two compartments one of said compartments serving to house the tuning elements of the radio apparatus and coating the inside surface of at least the compartment adapted to 7 house the tuning elements with a spray of shielding material.

2. The steps in a method of constructing radio cabinetswhich comprise dividing the cabinet interior into at least two compartments into one of which the tuning elements of the radio apparatus are adapted to be housed and coating the inside surface of. the compartment adapted to house the tuning elements witha layer of metal applied in a pulverized state.

CORNELIS BOL. 

